FIG. 6.

Analysis of 2Nt export activity in A9 mouse fibroblasts. (A) Transport of MVM particles. The native and heated MVM particles illustrated in Fig. 3A were injected into the nuclei of either growing or synchronized and MVMp-infected (1 PFU/cell) mouse fibroblasts at 6 hpi and then were stained with the α-CAP antiserum. The infection onset in some cells was demonstrated by staining with the α-NS1 antiserum. Representative fields of injected cells (two panels for infection studies) denoting intact nuclear membranes are shown. (B) Transport activity of 2Nt for a heterologous protein. The localization of phosphorylated (2Nt) and unphosphorylated [2Nt(−p)] peptides coupled to BSA and microinjected into the nuclei of uninfected (upper panels) or MVMp-infected (lower panels; injection at 14 hpi) A9 mouse fibroblasts is shown. The subcellular distribution of the conjugates was examined by confocal microscopy with the α-BSA and α-2Nt antisera. Shown are representative cells for each experiment.